The present invention relates to a process and an installation for the distribution of air enriched in oxygen to the passengers of an aircraft, more particularly a commercial airliner.
During accidental depressurization of the cabin of an airplane, at high altitude, the occupants (passengers and crew) must rapidly inhale air enriched in oxygen, so as to avoid a condition of hypoxia, due to the abrupt decrease in the partial pressure of oxygen.
To this end, it is known to provide independent means, permitting supplying air enriched in oxygen. It can be high pressure cylinders, in which is stored pure oxygen. Alternatively, it can be produced by means of chemical oxygen generators.
The distribution of oxygen to the passengers, from supply means, takes place by means of masks. These latter permit a mixture of distributed oxygen and ambient air. Distribution is stopped when the aircraft regains a low altitude of about 3,000 meters, which is reached about 15 minutes from a beginning altitude of about 12,500 meters.
This known solution however has certain drawbacks.
In particular, given that, in the case of depressurization, the aircraft must necessarily regain a relatively low altitude, about 3,000 meters, it is indispensable to retain in the fuel tanks a supplemental fuel quantity. Thus, the consumption of the aircraft is increased at this low altitude, because of the greater air resistance. It will be easily be seen that the carrying of this supplemental fuel contributes to increasing the weight of the apparatus significantly.
The invention proposes to use a process for the distribution of air enriched in oxygen, permitting overcoming this drawback.
To this end, it has for an object a process for the distribution of air enriched in oxygen to passengers of an aircraft, in which there is supplied to the passengers a first fraction of air enriched in oxygen from an independent source, during a descent phase of the aircraft between a cruising altitude and a re-routing altitude, and there is produced, in an onboard separator, a second air fraction enriched in oxygen, which is delivered to the passengers, at least during a substantially stabilized phase of the flight of the aircraft, taking place at about the re-routing altitude.
The invention permits achieving the objects mentioned above.
Thus, according to the invention, the onboard separator can produce air enriched in oxygen, from a source of compressed air belonging to the aircraft, for a very great period of time. The passengers are thus able to be supplied with air enriched in oxygen, not only during the time of descent, but also during the re-routing flight itself.
It will thus be easily seen that the altitude of rerouting can, because of this fact, be substantially greater than that of the prior art. Thanks to the process of the invention, it is thus possible to be able to re-route at altitudes greater than 5,500 meters, preferably comprised between 6,000 and 8,000 meters, permitting avoiding most of the high mountains on earth. By way of comparison, with the process using the solution of the prior art, such a rerouting altitude would require supply means, such as cylinders or generators, whose size and mass would be unacceptable.
Moreover, the quantity of reserve fuel, which must be kept in tanks of the aircraft, is substantially reduced thanks to the invention. Thus, the re-routing altitude permitted by the invention gives rise to a substantial decrease in the consumption of fuel relative to the prior art, which requires achieving a much lower altitude. The reduction of this supplemental quantity of fuel thus ensures a corresponding decrease in the weight of the aircraft, as well as its consumption. Moreover, this reduction of volume of onboard fuel permits the carrying of additional occupants or baggage, which is economically advantageous.
Given that the invention permits higher rerouting altitudes, it permits, as mentioned above, airline companies to design new routes, overflying mountainous regions. Such a possibility of advantageous to the extent to which it is able to reduce the duration of the flights. It should be remembered that the routes referred to above are up to the present forbidden, when they fly above regions whose altitude is greater than the re-routing altitude permitted by the prior art.
Finally, the invention permits avoiding the transportation of heavy gaseous oxygen cylinders or overdimensioned onboard oxygen generators. This guarantees a decrease in weight of the apparatus, and considerably reduces the risks of explosion during onboard fires.
The invention also has for its object an installation for supplying air enriched in oxygen to the passengers of an aircraft, comprising an independent source of a first fraction of air enriched in oxygen, onboard means for the production of a second fraction of air enriched in oxygen, means to deliver the first and second fractions of air enriched in oxygen to the passengers, and means (14) for sequential distribution of the respective flows of the first and second fractions of air enriched in oxygen to the delivering means (20, 22, 23).